This subproject is designed to determine the functional significance of morphologically different cell types in mammalian taste buds. Several different markers identify at least two types of taste cells in mammalian taste buds. The investigator proposes to patch clamp the cells from fungiform papillae in an intact section of lingual epithelium and correlate their basic electrophysiological properties as well as their taste responsiveness to their morphology. This work will be done in collaboration with Dr. Timothy Gilbertson, an electrophysiologist trained in patch clamp technology. Following recording, during which time the cells will be labeled by dye loading through the patch electrode, the cells will be fixed, sectioned, and characterized immunocytochemically as to morphological type. Some experiments will focus on taste cells from genetically engineered mice that are deficient in gustducin, a taste transduction protein thought to be characteristic of cell types responsive to sweet and bitter tastants, and a marker protein for one of the two types of taste cells.